Electric upsetting machine

ABSTRACT

An electric upsetting machine comprising an upsetting device, a pair of clamping electrodes, an anvil electrode and a transformer, the clamping electrodes being arranged in at least two adjacent pairs arranged to operate in parallel.

United States Patent Bachmann [1 1] 3,728,887 1451 Apr. 24, 1973ELECTRIC UPSETTING MACHINE Horst Bachmann, Einberg, Coburg, Germanyinventor: near Assignee: Langenstein & Schemann Aktier igesellschaft,Coburg, Germany Filed: Jan. 6, 1971 Appl. No.: 104,233

US. Cl. ..72/3l8, 72/342, 219/150 Int. Cl. ..B21j 5/08 Field of Search..72/306, 318, 342;

[56] References Cited UNlTED STATES PATENTS 1,940,264 12/1933 Monroe..219/150 2,305,961 12 1942 Gaspar ...219 15o 2,220,535 11 1940 Mora..219/150 Primary Examiner-Lnwel1 A, Larson I Attorney1-1olman & SternABSTRACT An electricupsetting machine comprising an upsetting device, apair of clamping electrodes, an anvil electrode and a transformer, theclamping electrodes being arranged in at least two adjacent pairsarranged to operate in parallel.

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' SHEET 5 0F 5 liq-i INVENTOR ELECTRIC UPSETTING MACHINE The inventionrelates to an electric upsetting machine comprising an upsetting device,a pair of clamping electrodes, an anvil electrode and a transformer. Thepair of clamping electrodes, also called guide electrodes, serve toguide a workpiece which is upset against the anvil electrode by theupsetting device.

A known machine of this type is provided with a single guide electrodeand a single transformer and this guide electrode is constructed as amechanical sleeve which encloses the workpiece to be upset. Thedisadvantage here is that this machine can only press one workpiece at atime and the machine can always only be arranged in such a way that onlyworkpieces of a certain range of thickness can be worked.

It is the object of the invention to provide a machine of the previouslymentioned kind, whose operational possibilities are greater than thoseof the known electric upsetting machines.

This invention provides an electrical upsetting machine comprising anupsetting device at least two pairs of adjacent clamping electrodesoperable in parallel and electrically insulated from one another, anvilelectrode, and a transformer for each pair of clamping electrodes, saidtransformers being arranged so that each transformer is electricallyconnected to only one of the pairs of clamping electrodes and all thetransformers are electrically connected with the anvil electrode.

This apparatus is thus an electric upsetting machine having variousoperational possibilities.

Two or more than two workpieces can be worked upon simultaneously with amachine according to the invention. The workpieces can betransported bymeans of parallel displacement between two clamping electrodes and canbe transported from one pair of clamping electrodes to the next, withoutbeing displaced in the direction of their lengths. In this process, thecurrent flow through each of the workpieces arising between the pair ofclamping electrodes and the anvil electrode is independent from thecurrent flow through the other workpieces.

It is preferable that each clamping electrode of each pair of clampingelectrodes is respectively connected through a circuit to a guideelectrode conductor of the corresponding transformer. In this way, animprovement of the current flowing from the clamping electrodes to theworkpieces is attained. Further increase of operational possibilities ofthe machine is attained if a clamping jaw, respectively electricallyinterconnecting the two clamping electrodes, is removably secured to theadjacent clamping electrodes of at least two pairs of clampingelectrodes. In this construction one workpiece can be operated upon byusing the power of two transformers. Conveniently, corresponding to thenumber of guide electrodes, there are provided at least two upsettingcylinders and the pressure rise in each of these cylinders causesrelease of a switching process which is related to the lengths of theworkpieces acted upon by the cylinders. In this way workpieces ofdifferent initial lengths can be upset independently from one another.

The drawings illustrate a preferred embodiment and show in:

FIGS. la and 1b a side view of an electric upsetting machine,

FIGS. 2a and 2b a section on the line 11-" in FIG. 1,

FIG. 3 a section on the line Ill-III in FIG. 1.

Two clamp slides l, 2 are arranged one above the other on the machineshown in FIGS. 1 to 3. The upper clamp slide 1 is movable up and downbetween two guides 3 and the lower clamp slide 2 is similarly movable upand down between two guides 4. Arranged below the lower clamp slide 2 isa clamping cylinder 5, whose piston rod engages the lower clamp slide.The piston rod of a clamping cylinder 6, arranged above the upper clampslide 1, likewise engages the upper clamp slide 1. The two clamp slides1, 2 respectively carry, at their facing sides, two pairs of clampingelectrodes 7 and 8, the electrodes of each pair being horizontallyadjacent and insulated from one another by an-insulating layer 56. Aclamping jaw 9 is arranged on each of the two upper clamping electrodes7, and each of the lower clamping electrodes also carries a clamping jaw10. Each of the two pairs of clamping jaws 9, 10 carries a workpiece 11,12 in the shape of a rod shaped blank. Each workpiece 11, 12, while itremains a blank, projects from the clamping jaws 9, 10 on one side as ashort section, and on the other side as a long section.

Co-axially arranged with respect to each pair of clamping jaws 9, 10 isa die 13, 14. The two dies 13, 14 are almost adjacent and are bothpartially fitted into an anvil electrode 15 which is cup-shaped andwhich takes the place of several individual anvil electrodes, and isfitted on a vertically arranged contact plate 16. Respectively arrangedabove and below the anvil electrode are contact pieces 17. Provided onthe side of the said contact plate 16, which is presented away from theanvil electrode 15, are two further adjacent contact plates 18 parallelto the said contact plate 16. Provided behind these contact plates 18 isan abutment 19 of an anvil slide 20 which carries the previouslymentioned parts and is displaceable in a horizontal direction. A support21 is arranged on the anvil slide 20. This is spaced from the abutment.Spaced behind the anvil slide 20 is a further cylinder 22 which carriesan extension 23 on its upper forward end. A spindle 24 passes throughthe extension 23 and the support 21, and carries respective nuts 25 onboth sides of the extension 23 and the support 21. This arrangement thussecures the spindle 24 in a releasable manner. The further piston,whichprojects from the cylinder 22, carries a block 26 having frontallyarranged two parallel upsetting mandrels 27, 28 which project throughthe support 21, the abutment 19, the contact plate 16 and the contactplates 18, and into the two dies 13, 14.

Arranged in front of the long sections of the workpieces 11, 12 is acasing 29 in which are housed two upsetting cylinders (not shown) of anupsetting device. The piston rod of an upsetting piston 30 projectsbackwardly from each cylinder carrying an upwardly directed bar 31 onits projecting end. An extension 32 is provided on the casing 29 foreach of these pistons 30. A spindle 33 projecting through each extension32 is connected to the bar 31 and carries a nut 34 between the extension32 and the bar 31. Each upsetting piston 30 being hollow at itsprojecting end, contains a movable threaded spindle 35, which projectsbackwardly and carries a nut 36 which is supported opposite theassociated piston 30.

A fixed transformer 37, 38 is respectively provided above and below theanvil slide 20, each having two electric conductors 39, 40, one of whichleads to the contact plate 16 and the other to the further contact plate18. The conductors 39, 40 of the upper transformer 37 are arranged ontop of the contact plates 16, 18 and the conductors of the lowertransformer 38 on the bottom. The rear contact plates 18 are connectedto the four contact pieces 17 by means of four contact bolts 56projecting through the front contact plate 16, whereby two contact bolts56 and two contact pieces 17 are respectively provided at the top and atthe bottom. An electric conductor 41 leads from each contact piece 17 toone of the four clamping electrodes 7, 8 whereby two of these conductors41 pass above the dies 13, 14 and the other two pass below the dies. Theconductors 39, 40, 41 are flexible.

The two contact plates 18, the four contact bolts 56 and the contactpieces 17 are electrically interconnected, but from the remainder of theapparatus are insulated. There is thus a current loop for the uppertransformer 37. This current loop runs from one conductor 40 and overone of the two contact plates 18 and is divided there, so that it runsthrough the upper contact bolt 56, upper contact piece 17, upperclamping electrode 7 and upper clamping jaw 9, it also runs through thelower contact bolt 56, lower contact piece 17, lower clamping electrode8 and lower clamping jaw 10 to the workpiece 11. The current loop iscompleted through the workpiece 11, the die 14 or anvil electrode 15,contact plate 16 and conductor 39. There is a similar current loop forthe transformer.38, whereby the current supply runs through theworkpiece 12.

A frame is provided comprising two front columns 42, two center columns43 and two back columns (not shown). The columns carry two spaced,parallel slideways 45. On their inwardly facing sides the two slideways45 have guide tracks, on which a plate 46 is located, the plate 46carrying the casing 29 and being secured to the slideways. A plate 47engaged on the rear of the guide tracks is also secured thereto andcarries the further cylinder 22. Furthermore, the anvile slide ismovable and is secured against vertical removal by means of a coverstrip 49.

The lower transformer 38 is mounted upon a support 50 which rests on theground. The upper transformer 37 is attached to the support 51 and isfurther supported from two diagonal trusses 52, each of which connects acenter column 43 and a rearcolumn. Arranged between the front columns 42and the center columns 43 is a sub-frame 53 whose lower cross beam isengaged by the lower clamping cylinder 5. Each of the center columns 43carries above it a support arm 44. Fixed to this support arm is asub-frame 55 whose upper cross-beam is engaged by the upper clampingcylinder 6. The two sub-frames 53, 55 carry the respective guides 3, 4.The clamping slides 1, 2 are movable in the guide-tracks of therespective guides 3, 4 and are held by means of strips 54. Support armsmay alternatively be employed to permit free lateral access to theclamping electrodes.

The electric upsetting machine according to the invention can heat upand form rod shaped workpieces in a wide area of differentcross-sectional sizes with maximum economy. In this process two rods aresimultaneously heated up and formed in the lower part of the work zonewhile in the upper part of this zone only one rod may be heated up andformed. Furthermore, complex head shapes can be produced and rodmaterial of a smaller size can be used. More complex head shapes can beproduced in two stages. The blank can be partially pre-heated during thefirst stage. With the aid of a current control device controlling thecircuit, the heating-up speed during the parallel upsetting of two rodscan be controlled independently and the workpiece can be transportedhorizontally through the machine without lifting or longitudinaldisplacement. It has also been taken into consideration that apredetermined heating-up and forming speed cannot be exceeded if perfecthead shapes are required and if the quality of the material is not to beimpaired. The limits are visible, for instance by two great a currentdensity at the contact surfaces of the clamping jaws, and sometimes alsoat the anvil plate. Since the system for controlling the currentaccording to the invention assures equal current flow into bothworkpieces, it is possible simultaneously to heat up and form twoblanks. It is known that electric current flows through a member oflowest resistance, that is to say, that more current would flow throughthe workpiece having the lowest electrical resistance and would thus beheated up more quickly than the other. Apart from the specificresistance of the workpiece there are a number of other factors whichcould act in this sense, for example, the effect of the electric fieldwhich is also influenced by the current control.

The method of manufacturing workpieces in which the cross-sectionschange lengthwise described in the German Pat. No. l,268,941 can beimproved according to the invention in such a way that the section withthe smaller cross-section is produced in the first die, and that thesection having the greater cross-section is produced in the second die.In the method of the above patent, two die sleeves are arranged withinone another. The smaller one is displaced during the pressing of thesection having the smaller cross-section and thus slides in the outersleeve. This tool construction has the disadvantage that the innersleeve cannot be cooled adequately and is therefore subject torelatively high abrasion. This can be essentially simplified in theabove described two stage method, by using a simpler cylindrical anvilplate as the small head, instead of using a relatively thinner anvilsleeve. For this it is necessary that the two dies are immediatelyadjacent in order to enable fast transfer to take place and to avoidheat loss in the section already formed. This is not possible withjoined individual units, since the distance from die to die isinevitably greater.

Secondly it is necessary that the electric current to the zones of therod to be heated can be independently controlled and adjusted withoutelectrically insulating the dies or anvil tools against one another.Thus, the two dies or anvil tools can be arranged immediately adjacentto one another and the operations in the two dies can be carried outcompletely independently.

By the arrangement of the current control according to the invention, itis possible to connect the clamping electrodes co-axially with theworkpiece blank to the,

progress of the rod can be carried out optionally from the left to theright or vice versa. Moreover, this structure provides all round accessto the tools and to other functional parts. Sometimes two rods can be ofdifferent lengths while being simultaneously formed. The machine istherefore equipped with a special device which balances the differencein lengths before the start of an upsetting process and so that both rodends have pressure applied to them at the anvil electrode at thebeginning of the operation and that the same volume of material isdeformed on each of the rods.

Two independently operating upsetting cylinders are provided to enabletwo different operations to be carried out simultaneously, for instanceduring the upsetting of parts with cross-sections which may varylengthwise of the parts.

The electric upsetting machine according to the invention can haveseveral operational variations, that is, simultaneous die upsetting oftwo rods, simultaneous free upsetting of two rods, die upsetting of onerod and free upsetting of one rod. The change-over from die upsettingwith two workpieces to free upsetting with two workpieces takes place asfollows: An anvil plate is fixed in front of each die. The furthercylinder is tightly connected to the anvil slide and the lock of theanvil slide is released. Subsequently, the upsetting stroke and theanvil stroke are corrected, the pressure for upsetting and the electriccurrent power are adjusted and the machine is ready to operate. Thechange-over from upsetting of two workpieces to upsetting of oneworkpiece to free upsetting takes place in such a way that the two anvilplates in front of the dies are replaced by a centrally arranged plate.The two pairs of clamping jaws are removed and replaced by a bigger pairof clamping jaws, the latter being inserted in the center of the twoclamping electrodes and both are electrically connected.

The following describes a heating up and forming process. Two rod blanksare inserted for instance into the lower clamping jaws of the machinewhich is ready for work. The machine is switched on by a foot or handswitch, the upper clamp slide comprising the clamping electrode and thenslides downwards, and after that the lower clamping slide comprising theclamping electrodes slides upwards. By this means the rods are securedinto the clamping jaws. The anvil slide, which occupies its right handposition is tightly locked during the die upsetting process. The furthercylinder of the machine is always, when the machine is renderedoperational, in the right hand position. After the rods are securedradially, the upsetting cylinders move in the direction of the clampingelectrodes and now also secure the rods between the anvil and theupsetting cylinder in a longitudinal direction. lf two independentlyoperating upsetting cylinders are provided the length variations betweenthe two blanks are balanced by moving the positions of the cylinders. Asa result of securing of the rods, the pressure in the upsettingcylinders rises and thereby automatically operates a hydraulic pressureswitch which connects the heating current and thus initiates theprocess. During the heating up and forming, the further cylinder withthe mandrels, withdraws and the upsetting cylinders press axially withconstant force onto the rods and effect the forming. During thisprocess, each of the two upsetting cylinders runs through apredetermined stroke. As soon as one of the two cylinders has reachedthe final position, the heating current of the rod concerned is switchedoff. As soon as both cylinders have reached their final positions, theclamping jaws open and the upsetting cylinders travel back to theiroriginal positions. Afterwards, the further cylinder also travels backinto the starting position and thereby ejects the working pieces throughthe mandrels. The working pieces can now be removed from the machine.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. An electric upsetting machine comprising an upsetting device a pairof clamping electrodes, an anvil electrode and a transformer,characterized in that at least two pairs of adjacent clamping electrodesare provided which operate in parallel.

2. An electrical upsetting machine comprising an upsetting device, atleast two pairs of adjacent clamping electrodes operable in parallel andelectrically insulated from one another, an anvil electrode, and atransformer for each pair of clamping electrodes, each said transformeris electrically connected to only one of the pairs of clampingelectrodes and all the transformers are electrically connected with theanvil electrode.

3. A machine according to claim 2, wherein a first contact plate isattached to the anvil electrode, at least two further contact plates,each electrically connected with one of the transformers, are providedon one side of the first contact plate, contact pieces are provided onthe other side of the first contact plate and are connected byelectrical conductors with respective pairs of clamping electrodes, andcontact bolts on the further contact plates extend through the firstcontact plate and are attached to the respective contact pieces so thatone of the further contact plates is connected with each pair ofclamping electrodes.

4. A machine according to claim 2, wherein the anvil electrode iscup-shaped and is arranged to receive at least two dies.

5. A machine according to claim 2 wherein two pairs of clampingelectrodes and two transformers are provided, one of the twotransformers being arranged above and the other transformer beingarranged below the two pairs of clamping electrodes.

6. A machine according to claim 2; wherein a cylinder is provided, saidcylinder having a piston provided with at least two upsetting mandrels.

7. A machine according to claim 6 wherein the anvil electrode isarranged on a movable anvil slide which can be fixed at varyingdistances from the cylinder, the said piston is connected to an anvilslide, and the anvil electrode is mounted for movement with the anvilslide.

8. A machine according to claim 2, wherein an upsetting cylinder isprovided for each pair of clamping electrodes, the pressure rise in eachof these upsetting cylinders being arranged to cause operation of aswitching process which is related to the length of a workpiece actedupon by the said cylinder.

9. A machine according to'claim 8 characterized in that each of theupsetting cylinders is provided with a hydraulic pressure switch whichenergizes the current circuit of one of the transformers.

10. A machine according to claim 8, wherein each of the upsettingcylinders has a stroke adjusting device in 13. A machine according toclaim 12 characterized in that a clamping cylinder which moves the upperclamping electrode of the pairs of clamping electrodes in a verticaldirection, is fixed to a support arm on a column.

14. A machine according to claim 2, constructed so as to be capable ofoperation as a die upsetting machine.

15. A machine according to claim 2, constructed so as to be capable ofoperation as a free upsetting machine.

1. An electric upsetting machine comprising an upsetting device a pairof clamping electrodes, an anvil electrode and a transformer,characterized in that at least two pairs of adjacent clamping electrodesare provided which operate in parallel.
 2. An electrical upsettingmachine comprising an upsetting device, at least two pairs of adjacentclamping electrodes operable in parallel and electrically insulated fromone another, an anvil electrode, and a transformer for each pair ofclamping electrodes, each said transformer is electrically connected toonly one of the pairs of clamping electrodes and all the transformersare electrically connected with the anvil electrode.
 3. A machineaccording to claim 2, wherein a first contact plate is attached to theanvil electrode, at least two further contact plates, each electricallyconnected with one of the transformers, are provided on one side of thefirst contact plate, contact pieces are provided on the other side ofthe first contact plate and are connected by electrical conductors withrespective pairs of clamping electrodes, and contact bolts on thefurther contact plates extend through the first contact plate and areattached to the respective contact pieces so that one of the furthercontact plates is connected with each pair of clamping electrodes.
 4. Amachine according to claim 2, wherein the anvil electrode is cup-shapedand is arranged to receive at least two dies.
 5. A machine according toclaim 2 wherein two pairs of clamping electrodes and two transformersare provided, one of the two transformers being arranged above and theother transformer being arranged below the two pairs of clampingelectrodes.
 6. A machine according to claim 2, wherein a cylinder isprovided, said cylinder having a piston provided with at least twoupsetting mandrels.
 7. A machine according to claim 6 wherein the anvilelectrode is arranged on a movable anvil slide which can be fixed atvarying distances from the cylinder, the said piston is connected to ananvil slide, and the anvil electrode is mounted for movement with theanvil slide.
 8. A machine according to claim 2, wherein an upsettingcylinder is provided for each pair of clamping electrodes, the pressurerise in each of these upsetting cylinders being arranged to causeoperation of a switching process which is related to the length of aworkpiece acted upon by the said cylinder.
 9. A machine according toclaim 8 characterized in that each of the upsetting cylinders isprovided with a hydraulic pressure switch which energizes the currentcircuit of one of the transformers.
 10. A machine according to claim 8,wherein each of the upsetting cylinders has a stroke adjusting device inwhich a threaded spindle can be secured into a piston of the upsettingcylinder and can be secured thereto by means of a nut.
 11. A machineaccording to claim 8, wherein each of the upsetting cylinders has astroke adjusting device in which a bar, which is fixed to a piston ofthe upsetting cylinder, carries a spindle having a nut which is securedto a relatively fixed extension opposite to the upsetting cylinder. 12.A machine according to claim 2, wherein two horizontally adjacentclamping electrodes are arranged for vertical movement in a commonslide.
 13. A machine according to claim 12 characterized in that aclamping cylinder which moves the upper clamping electrode of the pairsof clamping electrodes in a vertical direction, is fixed to a supportarm on a column.
 14. A machine according to claim 2, constructed so asto be capable of operation as a die upsetting machine.
 15. A machineaccording to claim 2, constructed so as to be capable of operation as afree upsetting machine.